Link-motion for steam-engines.



ND. 705J74.

Patented July 22, I802; M. A. WHARE-BELD. LlNK MOTION FOR STEAM ENGINES.

(Application filed Dec. 9, 1901.)

(No Model.)

Fig.1.

VENT'TOR:

MARION A. WHARFIELD, OF TOLEDO, OHIO, ASSIGNOR OF EIGHT-FIFTEENTHS TO BENSON G. MCMEOHEN AND HENRY O. WHARFIELD, OF TOLEDO, OHIO.

LINK-MOTION FOR STEAM ENGINES.

SPECIFICATION forming part of Letters Patent No. 705,174, dated July 22, 1902.

Application filed December 9, 1901. Serial No. 85,165. (No model.)

To all whom it may concern.-

Be it known that I, MARION A. WHARFIELD, a citizen of the United States, residing at T0- ledo, in the county of Lucas and State of Ohio, have invented certain new and useful Improvements in Link-Motions for Steam-Engines; and I do declare the following to be a full, clear, and exact description of the invention, such as willenableothers skilled in the art to Which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification.

My invention relates to a link for controlling and reversing the movement of steamvalves for steam-engines; and its object is to provide a simple easily controlled device whereby the valve shall be thrown into open or closed position rapidly, thus giving a sharp cut-off and exhaust.

The further object of my invention is to reduce to a minimum the movements and vibration of the link.

I attain these objects by means of the devices and arrangement of parts hereinafter described, and shown and illustrated in the accompanying drawings, in which-- Figure 1 is a side elevation ofan upright reciprocating steam-engine provided with my link-motion; Fig. 2, a side'elevation of my device detached; Fig. 3, a side elevation of the pieces, hereinafter referred to,comprising my link; and Fig. 4, a central Vertical transverse sectional elevation of the part shown in Fig. 3 in place, taken on line a a, Fig. 2.

Like numerals of reference indicate like parts throughout the drawings.

In the drawings, 1 is the crank shaft of the engine, driven by connecting-rod 2. Upon the crank-shaft is a single cam 8 and camstrap 4. The latter is provided with an arm 5. 6 is an open link curved in the arc of a circle. Projecting at a right angle from the a bell-crank lever. At its angle this lever is enlarged and has an elongated opening 8, which is designed to receive and to embrace loosely the crank-shaft of the engine. The link 6, the shaft 7, and the lever 8 are formed in one piece. The arm 5 of the cam 4 and the arm 8 of the lever 8 lie side by side and at their extremities are pivotally connected together by means of a pin 8, projecting laterally from the extremity of the arm 8 which pin engages a corresponding hole in the extremity of the arm 5.

Secured in the curved slot of the link is a sliding block 10, to which is pivotally secured the valve-rod 11,which is connected with and controls the valve of the engine in the usual manner. 12 is a rod pivotally connected at one end to the block 10 and pivotally conneoted at its other end to the reversing-lever 13, which lever is adapted to move the block the full length of the link and determines the position of the block 10 relatively to the link 6. This lever is provided with a suitable detent for holding it set at any desired position. In the example shown in the drawings the le ver carries a small pinion 14, which meshes with and rides upon a toothed quadrant 15 and which is normally engaged by the detent illustrated in dotted lines in Fig. 1.

The operation of my device is as follows: The parts being assembled as shown and described and steam being admitted. to the engine through the valve-chamber, the throw of the valve and consequently the amount of steam used will depend upon the position of the block 10 in relation to the link 6. This position is governed by means of the reversin'g-lever 13 in the usual manner. The throw of the arm 5 of the cam-strap 4 imparts a like motion to the arm 8 of the lever B, causing the link to swing on its shaft in the arc of a circle. The-shaft the end of which is secured to the side of the link exactly midway of its length forms a fixed fulcrum on which the link swings, thus avoiding the complicated endwise and sidewise movements usual in link motions. As the sliding blockis moved by the reversing lever the point of cutoff is varied or the steam is reversed or the valve is rendered inactive, according to the position of the block, as may be required. When the sliding block occupies a position in the link at any point between the middle and either end, it receives a motion great in proportion to its proximity to the end, and, conversely, when the block is set at exactly the middle of the link the rod 11 ceases to reciprocate, the valve becomes inoperative, and the engine stops. By shifting the block from the position shown to the position indicated by the dotted lines the admission of the steam and the motion of the engine are reversed.

It will be seen from the diagram in Fig. 2 that the movement of the extremities of the arms 5 and 8 at the point Where they are pivoted together is through a short are of the circle of which shaft 7 is the center and that while the engine is making but a small part of a revolution thelever 8 is thrown. Hence the swing of the link upon its beariugis rapid. The result is that the valve is moved quickly and the cut-off is clean.

It will be seen that the illustrated arrangement of the lever 8 8 with the elongated opening 8 for the reception of the crank-shaft permits the lever to be disposed in the engine, so as to take but little room and to give strength and rigidity to the lever, permitting the lever to be swung without interference from the shaft.

Having described my invention, what I claim, and desire to secure by Letters Patent, 1s

1. A link-motion comprising a link, a shaft projecting laterally from one side of the link midway between the ends of the link, stationary bearings for said shaft, connections between the shaft of the engine and the link which connections give to the link a single uniform motion on its hearings in harmony with the movement of the engine-shaft, a block in the link connected with the enginevalve, and means for controlling the position of the block relatively to the link, the arrangement being such that the block may be moved into and out of coincidence with the axis of motion of said link.

2. A link, stationary bearings on which the link rocks midway of its length andwidth, a cam on the engine-shaft set oppositely to the engine-crank, a cam-strap on the cam,and pivotal connections between the cam-strap and the link which pivotal connections are disposed in a line at a right angle to the line of the axes of the link-bearings and the en- 4 gine-shaft.

3. In a link-movement, a link, a shaft for said link projecting from one side thereof, the arrangement being such that the shafts axial line, extended, passes through the longitudinal and transverse center of the linkopening, a stationary bearing for said shaft, a block slidably mounted in the link, and means for rocking the link on its shaft in harmony with the motion of the engine-shaft.

4:. In a link-motion, a link, a shaft for said link midway of its length, a lever connected with said shaft and having two arms at substantially a right angle to each other and in a plane parallel to the link and having at the angle of the arms an elongated opening for the engine-shaft, said link, shaft and lever being integral.

In testimony whereof I affix my signature in presence of two witnesses.

MARION A. WIIARFIELD.

Witnesses:

F. 1. DOTSON, L. E. BROWN. 

